To judge the quality of the translation, I compared by reading selections from the first two chapters of Rascoe with the more recent translation by Permee published in the Oxford World Classics edition (1992).
In some ways I found Rascoe better, some scenes just make more sense and it flows more clearly. On the other hand, some scenes have clearly been sanitized and possibly even tampered. For example in Chapter 2, Nana is describing a return from a meeting, the nature of which has not been fully revealed:
1922: (tr. Burton Rascoe, p. 42)
"Do you think I have been amusing myself? I thought I should never have been able to get away. I should have liked to seen you in my place. I was boiling. I was on the point of using my fists."
1992 (tr. Douglas Parmee, Oxford World Classics, p.42)
"Do you think I got any fun out of it? It went on and on .. I'd like to see you doing it .. I could have smacked his face, I was so furious!"
Parmee is clearly the winner, saying much more and with passion, it's a lot clearer what Nana was doing. Given the high degree of sexual innuendo in the novel, I think the more recent translation is better, even though it feels a little harsher and less clear at times; but it is probably higher fidelity to the French (of which I can't compare). However if your able to read between the lines, I think Rascoe's version is more than competent and is freely available and closer to the time period in general sentiment.